The primary objective of this project is to cyclically maintain 3 filarial parasites by alternate passage through vertebrate and invertebrate hosts and supply limited amounts of these research materials to investigators. These filarial systems are as follows: (1) Brugia pahangi in jirds, dogs, cats, and Aedes aegypti (Liverpool strain) mosquitoes; (2) B. malayi in jirds, cats and A.aegypti; and (3) Dirofilaria immitis in dogs and A. aegypti.